For that all it s happening in your request
you have your category in your URL so use the $_GET array witch content all the var that u pass with your URL

then

do something like

$cat = $_GET['Category'];

and then
if($cat)
{
$result = mysql_query("SELECT * FROM ringtone WHERE category LIKE '$cat'",$db);
while($Row=mysql_fetch_array($result))
{
your code here to display all the ringtones from the wathever category
}
}

NB: this code supose dat ur field name in ur Db for the category is 'category'